mirror of
https://github.com/sqlite/sqlite.git
synced 2025-08-07 02:42:48 +03:00
Begin adding support for more esoteric window frames.
FossilOrigin-Name: bc4b81d60d40583de0f929730159011c1a7696802532ebd02220de3ace94a60d
This commit is contained in:
dan
212
src/window.c
212
src/window.c
@@ -66,4 +66,216 @@ int sqlite3WindowCompare(Parse *pParse, Window *p1, Window *p2){
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return 0;
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}
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void sqlite3WindowCodeInit(Parse *pParse, Window *pWin){
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Vdbe *v = sqlite3GetVdbe(pParse);
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int nPart = (pWin->pPartition ? pWin->pPartition->nExpr : 0);
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nPart += (pWin->pOrderBy ? pWin->pOrderBy->nExpr : 0);
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if( nPart ){
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pWin->regPart = pParse->nMem+1;
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pParse->nMem += nPart;
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sqlite3VdbeAddOp3(v, OP_Null, 0, pWin->regPart, pWin->regPart+nPart-1);
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}
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}
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/*
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** RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
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**
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** ...
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** if( new partition ){
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** AggFinal (xFinalize)
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** Gosub addrGosub
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** ResetSorter eph-table
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** }
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** else if( new peer ){
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** AggFinal (xValue)
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** Gosub addrGosub
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** ResetSorter eph-table
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** }
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** AggStep
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** Insert (record into eph-table)
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** sqlite3WhereEnd()
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** AggFinal (xFinalize)
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** Gosub addrGosub
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**
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** RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
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**
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** As above, except take no action for a "new peer". Invoke
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** the sub-routine once only for each partition.
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**
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** RANGE BETWEEN CURRENT ROW AND CURRENT ROW
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**
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** As above, except that the "new peer" condition is handled in the
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** same way as "new partition" (so there is no "else if" block).
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**
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** RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
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**
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** One way is to just reverse the sort order and do as for BETWEEN
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** UNBOUNDED PRECEDING AND CURRENT ROW. But that is not quite the same for
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** things like group_concat(). And perhaps other user defined aggregates
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** as well.
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**
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** ...
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** if( new partition ){
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** Gosub flush_partition;
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** ResetSorter eph-table
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** }
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** AggStep
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** Insert (record into eph-table)
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** sqlite3WhereEnd()
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** Gosub flush_partition
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**
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** flush_partition:
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** OpenDup (csr -> csr2)
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** foreach (record in eph-table) {
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** if( new peer ){
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** while( csr2!=csr ){
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** AggStep (xInverse)
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** Next (csr2)
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** }
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** }
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** AggFinal (xValue)
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** Gosub addrGosub
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** }
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**
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**========================================================================
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**
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** ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
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** ...
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** if( new partition ){
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** AggFinal (xFinalize)
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** }
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** AggStep
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** AggFinal (xValue)
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** Gosub addrGosub
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** sqlite3WhereEnd()
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**
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** ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
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** ROWS BETWEEN CURRENT ROW AND CURRENT ROW
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** ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
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**
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**========================================================================
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**
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** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> PRECEDING
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** ROWS BETWEEN <expr> PRECEDING AND <expr> PRECEDING
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** ROWS BETWEEN <expr> PRECEDING AND CURRENT ROW
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** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> FOLLOWING
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** ROWS BETWEEN <expr> PRECEDING AND <expr> FOLLOWING
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** ROWS BETWEEN CURRENT ROW AND <expr> FOLLOWING
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** ROWS BETWEEN <expr> FOLLOWING AND <expr> FOLLOWING
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** ROWS BETWEEN <expr> PRECEDING AND UNBOUNDED FOLLOWING
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** ROWS BETWEEN <expr> FOLLOWING AND UNBOUNDED FOLLOWING
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**
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** Cases that involve <expr> PRECEDING or <expr> FOLLOWING.
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**
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** ...
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** Insert (record in eph-table)
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** sqlite3WhereEnd()
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**
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*/
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void sqlite3WindowCodeStep(
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Parse *pParse,
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Select *p,
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WhereInfo *pWInfo,
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int regGosub,
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int addrGosub
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){
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Vdbe *v = sqlite3GetVdbe(pParse);
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Window *pWin;
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Window *pMWin = p->pWin;
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int k;
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int iSubCsr = p->pSrc->a[0].iCursor;
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int nSub = p->pSrc->a[0].pTab->nCol;
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int reg = pParse->nMem+1;
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int regRecord = reg+nSub;
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int regRowid = regRecord+1;
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int addr;
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pParse->nMem += nSub + 2;
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/* Martial the row returned by the sub-select into an array of
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** registers. */
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for(k=0; k<nSub; k++){
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sqlite3VdbeAddOp3(v, OP_Column, iSubCsr, k, reg+k);
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}
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/* Check if this is the start of a new partition or peer group. */
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if( pMWin->regPart ){
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ExprList *pPart = pMWin->pPartition;
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int nPart = (pPart ? pPart->nExpr : 0);
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ExprList *pOrderBy = pMWin->pOrderBy;
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int nPeer = (pOrderBy ? pOrderBy->nExpr : 0);
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int addrGoto = 0;
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int addrJump = 0;
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if( pPart ){
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int regNewPart = reg + pMWin->nBufferCol;
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KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);
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addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart, nPart);
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sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
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addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, 0, addr+2);
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for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
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sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, pWin->nArg);
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sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
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sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
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}
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if( pOrderBy ){
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addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);
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}
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}
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if( pOrderBy ){
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int regNewPeer = reg + pMWin->nBufferCol + nPart;
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int regPeer = pMWin->regPart + nPart;
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KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOrderBy, 0, 0);
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if( addrJump ) sqlite3VdbeJumpHere(v, addrJump);
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addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPeer, regPeer, nPeer);
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sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
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addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, 0, addr+2);
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for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
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sqlite3VdbeAddOp3(v,
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OP_AggFinal, pWin->regAccum, pWin->nArg, pWin->regResult
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);
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sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
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}
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if( addrGoto ) sqlite3VdbeJumpHere(v, addrGoto);
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}
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sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
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sqlite3VdbeAddOp1(v, OP_ResetSorter, pMWin->iEphCsr);
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sqlite3VdbeAddOp3(
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v, OP_Copy, reg+pMWin->nBufferCol, pMWin->regPart, nPart+nPeer-1
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);
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sqlite3VdbeJumpHere(v, addrJump);
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}
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/* Invoke step function for window functions */
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for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
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sqlite3VdbeAddOp3(v, OP_AggStep0, 0, reg+pWin->iArgCol, pWin->regAccum);
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sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
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sqlite3VdbeChangeP5(v, (u8)pWin->nArg);
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}
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/* Buffer the current row in the ephemeral table. */
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if( pMWin->nBufferCol>0 ){
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sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, pMWin->nBufferCol, regRecord);
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}else{
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sqlite3VdbeAddOp2(v, OP_Blob, 0, regRecord);
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sqlite3VdbeAppendP4(v, (void*)"", 0);
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}
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sqlite3VdbeAddOp2(v, OP_NewRowid, pMWin->iEphCsr, regRowid);
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sqlite3VdbeAddOp3(v, OP_Insert, pMWin->iEphCsr, regRecord, regRowid);
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/* End the database scan loop. */
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sqlite3WhereEnd(pWInfo);
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for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
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sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, pWin->nArg);
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sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
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sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
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}
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sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
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}
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